312.

The cut or depression below the lower lip of the mouth is half way
between the bottom of the nose and the bottom of the chin.

The face forms a square in itself; that is its width is from the
outer corner of one eye to the other, and its height is from the
very top of the nose to the bottom of the lower lip of the mouth;
then what remains above and below this square amounts to the height
of such another square, ab is equal to the space between cd; dn in the same way to nc, and likewise sr, qp, hk are equal to each other.

It is as far between m and s as from the bottom of the nose to
the chin. The ear is exactly as long as the nose. It is as far from
x to j as from the nose to the chin. The parting of the mouth
seen in profile slopes to the angle of the jaw. The ear should be as
high as from the bottom of the nose to the top of the eye-lid. The
space between the eyes is equal to the width of an eye. The ear is
over the middle of the neck, when seen in profile. The distance from
4 to 5 is equal to that from s to r.